Secondary service stops serving on shared IP after primary service changes PIP

[Liunardy]

What happened:

When two services share a public IP on a single-SLB cluster and the primary service moves to a different PIP (e.g. a user-assigned PIP), the secondary service no longer serves traffic on the original shared IP.

What you expected to happen:

The secondary service should still serve from the original shared IP when the primary service moves to a different PIP.

How to reproduce it (as minimally and precisely as possible):

1. Create a single-SLB cluster.
2. Create two external LoadBalancer services sharing the same public IP.
3. Create a PIP manually (user-assigned).
4. Update the primary service to target the user-assigned PIP.
5. Observe the secondary service no longer serves traffic on the original shared IP.

Anything else we need to know?:

Probably also happens if primary service moves to another managed PIP.
Haven't checked if the same also happens for internal services.

Environment:

• Kubernetes version (use kubectl version):
• Cloud provider or hardware configuration:
• OS (e.g: cat /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Network plugin and version (if this is a network-related bug):
• Others: